Walk-in bathtub



FIG. 1 is a front, top, left side perspective view of a walk-in bathtub door showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

Broken lines of the disclosure represent portions of the walk-in bathtub door that form no part of the claimed design. 

CLAIM We claim the ornamental design for a walk-in bathtub door, as shown and described. 